1. Field of the Invention
The present invention relates to an elastic membrane.
Such membranes are used, in particular, for the joining of the ends of railway cars in such a manner that they are protected from the air and the weather.
2. Description of the Related Art
The prior art includes elastic walls, for instance intermediate walls between two rail cars. They are intended to form a closure against the weather, smoke and dust. These walls comprise an externally visible plate of highly elastic material, for instance highly elastic rubber. On the inside of this plate there is fastened to the plate an undulated fabric which is embedded in plastic material, such as rubber or similar material.
Upon the displacement with respect to each other of the ends of the cars which are equipped with a connecting transition consisting of this material, for instance around curves, the outer plate is stretched due to its elasticity, the inner layer being also extended and the folds or corrugations being flattened until the inner layer is also in its final stretched condition, so that the extension of the wall is at an end.
A second such wall construction is present on the inner side of the first wall, the surface facing towards the inside being again developed as a flat, sheet-shaped surface, and the folds or undulated layer being fastened in this manner which has been described.
This elastic intermediate wall will absorb, with considerable elastic deformation, the stressing occurring in the longitudinal direction of the train, especially around curves, as a result of the increase in spacing between the parts of the car to the outside of the curve. However, such deformation is not possible in any other direction, for instance in height or laterally, since the inner surface with fabric insert selected does not permit this, in view of its construction and shape (U.S. Pat. No. 2,578,140).
An annular attachment of two cars in the form of a flexible covering is also known. It consists of two parts each connected to one of the vehicle ends. The two-part covering is provided with transverse corrugations which serve to compensate for a change in distance between the two ends of the car in the direction of travel. However, this transverse corrugation only inadequately permits three-dimensional changes in position of the ends of the two cars relative to each other. This possibility of adaptation of shape upon a three-dimensional relative change in position of the ends of the cars is necessary in particular when the two ends of the cars are relatively close to each other, or the intervening space is only of slight width (Federal Republic of Germany A 35 41 367).
The elastic membranes of this type which are known today have the disadvantage that they are not substantially free of stress, in particular free of tensile stress, in all three dimensions and therefore cannot meet certain requirements.